Medical fluid injection devices are typically used to inject a medical fluid, such as saline or contrast media, into a patient. These devices often include one or more reservoirs to hold the medical fluid, and one or more pressurizing units to inject the medical fluid into the patient. For example, a contrast media powered injection device may include a reservoir containing contrast media and a syringe that is used to inject the contrast media into the patient. The contrast media injection device may be used during certain medical procedures, such as angiographic or computed tomography (CT) or magnetic resonance imaging (MRI) procedures.
Many medical fluid injection devices include one or more pressurizing units (e.g., syringes, pumps, etc.) to inject fluid. A syringe, for example, may have a chamber for holding the fluid and a plunger that is moveable within the chamber. The fluid is typically drawn into the chamber from a fluid reservoir when the plunger is moved in a first direction (e.g., retracted). The fluid may subsequently be expelled from the chamber and into the patient, for example via a catheter, when the plunger is moved in a second, opposite direction (e.g., advanced). The fluid is expelled or delivered at a rate (e.g., a flow rate, typically measured in units of volume per unit of time) that may be determined by a speed of movement of the plunger.
A medical fluid injection device or system may include one or more fluid connectors to establish fluid flow paths between the injection device and the patient, and between various portions of the device/system. For example, some portions of a medical fluid injection system may include disposable components (e.g., sterile tubing), while other portions of the system may comprise reusable components designed for repeated uses (e.g., for multiple patients, or for multiple procedures). Certain disposable components may be further categorized as single-use or multiple-use components, for example. Establishing fluid connections between the various components of a fluid injection system may involve the use of fluid connectors adapted to facilitate making the connections (e.g., to make it relatively easy for an operator to make the connection), while also ensuring appropriate or adequate fluid properties around the site of the connections (e.g., air tight seal, no leaks in or out, etc.). In some cases, such fluid connectors may include a sealing component adapted to establish a fluid seal (e.g., to prevent leaks near the site of the fluid connection). The sealing component may employ a frictional or compressive aspect, for example, to achieve the fluid seal. O-rings, gaskets, and certain elastomeric fittings are examples of sealing components which may employ a frictional or compressive aspect to achieve a fluid seal in a fluid connector.
For patient safety, a medical fluid injection system may incorporate safety features and/or operating procedures designed to prevent the inadvertent injection of air into a patient. Safety features might include, for example, the ability of the medical fluid injection system to detect the presence of air or air bubbles in the medical fluid to be injected. The detection of air in the fluid may trigger a response, such as an audible or visible alarm to alert an operator, and/or an automatic termination of an injection, for example. An acoustic sensor (e.g., an ultrasonic sensor) is one example of an air detector that could be used to detect the presence of air in the fluid flow path. Operating procedures might include, for example, actions taken manually or automatically by the medical fluid injection system. For example, prior to a medical fluid injection into a patient, a purge procedure may be performed. A purge procedure might typically involve flushing fluid through the fluid flow path, thereby causing air that may exist in the fluid flow path to be pushed through and out of the flow path prior to establishing fluid flow to a patient. This could be done, for example, by using the medical fluid injection system to push or flush fluid through the system as part of a procedure, for example, in conjunction with filling the pressurizing unit with the medical fluid to be delivered.